A New Method of Force Calculation of Sucker Rod String in Directional Well

Abstract

The actual wellbore trajectory of the directional well is an irregular spatial curve which is not only distorted, but also bended compared to the straight well. The complexity of the shape makes the sucker rod string in the work of a complex state of alternating stress, and withstanding axial compression, torsion and bending of the coupling effect. Meanwhile, the phenomenon of eccentric wear and disconnection of the sucker rod string becomes worse and worse. Based on the actual force of the sucker rod string in the directional well and the different force characteristics, a new method of force calculation of sucker rod string in direction well is given in this paper, the mechanics analysis models of the sucker rod string in three-dimensional directional well have been deduced respectively. Through the combination of mathematical geometry and traditional mechanics, the mathematical model can be used to obtain the analytic solution of the mechanical problem of sucker rod string, which is suitable for engineering design calculation and overall evaluation research.